The present invention relates to a recognition data extracting device for use with an optical character reader (hereinafter abbreviated to "OCR" when applicable) in which light is applied to characters printed by a typewriter or a printer or hand-written characters and the characters are recognized by utilizing light reflected therefrom or for use with a magnetic ink character reader (hereinafter abbreviated to "MICR" when applicable) in which character recognition is carried out by reading with a magnetic head characters which are printed in special patterns with ink containing magnetic material.
Magnetic ink character readers have been employed in facilities such as banks to read data from and classify checks, bills, and the like. An example of magnetic ink characters which are used with an MICR is the CMC7 character font which is employed as the standard character font in various countries in Europe. On the other hand, the E13B character font as shown in FIG. 1 is employed in both America and Japan.
Conventional magnetic ink character readers can be classified into two groups. In one of the two groups, a matrix pattern system is employed in which magnetic heads of several tens of channels are provided to digitize characters. In the other groups, an analog pattern system is employed in which a single channel magnetic head is provided to convert characters into an analog waveform. Examples of a magnetizing device and a magnetic head for the analog pattern system are as shown in FIG. 2.
However, the magnetic ink character reader of the matrix pattern system is disadvantageous in that, as a number of channels are employed, the circuit is intricate in arrangement. Moreover, if characters are not correctly positioned with respect to the magnetic heads, errors due to tracking shift, etc. can arise which reduces the reliability of character recognition.
On the other hand, the magnetic ink character reader of the analog pattern system is advantageous in that such errors due to tracking shift, etc. can be prevented. However, it is still disadvantageous in that, as character recognition is carried out in an analog mode, the recognition circuit is necessarily intricate in arrangement and the output signal of the magnetic head is unstable, tending to cause errors, with the result that the reliability of character recognition is again somewhat low.
Referring to FIG. 2, a pad roller 3, made of non-magnetic material, is adapted to press a card 1 against a magnetic head 2. If stray magnetic ink particles 5 magnetized by a magnet 4 are stuck to the pad roller 3, then variations in magnetic flux are produced which are detected by the magnetic head 2 when the magnetic ink particles 5 pass the magnetic head 2 as the pad roller 3 is turned in the direction of the arrow. The detection of the particles produces an erroneous output as a character signal or signals. This erroneous detection is liable to occur especially when a blank portion of the card 1 where no characters 1a, 1a, . . . , 1a (FIG. 1) are printed passes through the magnetic head 2. This type of optical character reader thus suffers from the same difficulties as the magnetic ink characteristic reader.